The invention is directed to a catheter having a basket-shaped electrode array with an improved mechanism for expanding and retracting the electrode array.
Electrophysiology catheters are commonly-used for mapping electrical activity in the heart. Various electrode designs are known for different purposes. In particular, catheters having basket-shaped electrode arrays are known and described, for example, in U.S. Pat. No. 5,772,590, the disclosure of which is incorporated herein by reference. Such catheters are typically introduced into a patient through a guiding sheath with the electrode array in a folded position within the sheath so that the electrode array does not damage the patient during introduction. Within the heart, the guiding sheath is removed and the electrode array is permitted to expand to be generally basket-shaped. Some basket catheters include an additional mechanism in the form of a wire or the like connected to an appropriate control hand to assist in the expansion and contraction of the electrode array.
The present invention is directed to a catheter having a basket-shaped electrode assembly with an improved mechanism for expanding and contracting the electrode array. The expansion mechanism is designed to permit reproducible reintroduction of the catheter into the heart. In one embodiment, the catheter comprises an elongated catheter body having proximal and distal ends and at least one lumen therethrough. A basket-shaped electrode assembly is mounted at the distal end of the catheter body. The basket assembly has proximal and distal ends and comprises a plurality of spines connected at their proximal and distal ends. Each spine comprises at least one electrode. The basket assembly has an expanded arrangement wherein the spines bow radially outwardly and a collapsed arrangement wherein the spines are arranged generally along the axis of the catheter body. An expander is attached at or near its distal end to the distal ends of the spines and extends through the catheter body. The expander has a proximal end that extends out the proximal end of the catheter body a lumen extending therethrough. In use, the expander can be moved longitudinally relative to the catheter body to expand and contract the basket-shaped electrode assembly. The lumen that extends through the expander permits the catheter to be introduced into the heart over a guidewire. If the catheter is removed and subsequently reintroduced over the guidewire, the basket-shaped electrode assembly can be easily reintroduced to its original position.